"Titanic" is back, and millions of folks will stand in line for another chance to get sad. Really sad.

Why do people want to make themselves so miserable by watching a flick that shows dead babies floating in the frigid North Atlantic, and young love that ends in tragedy? Just as Leonardo DiCaprio finds romantic bliss, he's zapped. Really zapped.

Aristotle thought he had it figured out. "Tragic plays have the capacity to purify the spirit," he said. Huh? A tear-jerker leaves you purified?

Maybe not. But according to a new study from Ohio State University, it may at least leave you happier.

Researchers there put 361 college students through a brief encounter with misery to see what happens when people watch others get destroyed on the silver screen. They watched part of the British movie "Atonement," the story of star-crossed lovers who end up dead.

The participants were repeatedly asked about their emotions, and their thoughts, as they watched deception and tragedy unfold. They felt pretty good, it turns out, because the movie made them think about their own lives, and their own relationships.

Their lives, compared to the unfortunate lovers on the screen, were full of promise and good relationships and hopes for the future.

"What makes us happy in life are the people we are close to," Silvia Knobloch-Westerwick, lead author of the study, said in a telephone interview. She is an associate professor of communication at Ohio State, and describes herself as a "media psychologist."

Sadness on the screen, or in our real lives, is about loss. "Titanic" isn't about an ocean cruise. It's about dying. So is "Atonement." And dying is the ultimate manifestation of loss.

Movies, songs, and novels, are almost always about relationships. When a movie is particularly sad, it is because of a tragic relationship. So as the students in the Ohio study watched "Atonement," their thoughts naturally turned to their own relationships, with friends, family, and future loves.

"The movie made me think about how lucky I will be once I find someone worth that kind of love and commitment," one student wrote.

"This movie demonstrated that true love does exist and when you find it, it is so powerful that you will go to the ends of the earth to hold on to it," said another.

"I want to live my life to the fullest, and this movie has made we think a lot," said a third.

The study, published in the journal Communication Research, found that the more the students thought about their own relationships, either current or future, the happier they felt.

"If you are in a very sad and negative mood you will think more, and you will also think about close relationships, because those sad movies are very much about relationships," said Knobloch-Westerwick. "If you are in a positive mood, you are thinking everything's fine, so you are less thoughtful."

Most of the quotes in the study are indeed about relationships. And many show that the students were stimulated by the film to think seriously about the people in their lives, or the lack thereof.

"The movie makes me wonder if I'm wasting my time on all the wrong guys and if I will ever truly love someone that deeply that I would wait for them an eternity," one student noted.